Skip to main content

Advertisement

Table 1 Differences in survival rates between PIT-tagged and surgically implanted yearling and subyearling Chinook salmon

From: Survival of seaward-migrating PIT and acoustic-tagged juvenile Chinook salmon in the Snake and Columbia Rivers: an evaluation of length-specific tagging effects

  km Hockersmith et al. [12] Hockersmith et al. [14] Wargo-Rub et al. [15] Wargo-Rub et al. [16]
Detection location downstream RT PIT P value AT PIT P value AT PIT P value AT PIT P value
Yearling              
Little Goose Dam 60 0.62 0.598 0.307 1.00 0.89 0.004 0.93 0.93 0.893 0.92 0.95 0.107
Lower Monumental Dam 106 0.554 0.507 0.591 0.88 0.83 0.222 0.92 0.88 0.08 0.88 0.93 0.096
Ice Harbor Dam 157 NA NA NA NA NA NA 0.81 0.84 0.285 0.80 0.83 0.336
McNary Dam 225 0.328 0.343 0.427 0.70 0.79 0.102 0.72 0.78 0.054 0.68 0.75 0.095
John Day Dam 348 NA NA NA 0.61 0.65 0.538 0.62 0.72 0.01 0.60 0.83a 0.001
Bonneville Dam 460 NA NA NA 0.48 0.54 0.547 0.50 0.63 0.001 0.52 0.75 a 0.021
Subyearling   Wargo-Rub et al . [15]          
   AT PIT P          
Little Goose Dam 60 0.65 0.81 0.003          
McNary Dam 225 0.23 0.56 < 0.001          
  1. Fish were either surgically implanted with a sham radio transmitter (RT) containing an embedded PIT tag or an acoustic tag and a PIT tag (AT). All fish in these four studies were tagged at Lower Granite Dam (695 km upstream from the Pacific Ocean) and released in the Snake River just downstream of the dam. Fish were detected by PIT detectors at several downstream dams (distance downstream from release shown) on their seaward migration. The datasets from Hockersmith et al. [14] and Wargo-Rub et al. [15, 16] were used to assess length-specific tag effects.
  2. aIn 2008 at these two locations, the PIT data collected did not conform to statistical model assumptions and these estimates are considered problematic or inaccurate [20].
  3. AT acoustic transmitter, NA not applicable, RT radio transmitter, PIT passive integrated transponder.